GPL license & ExtASP

I would like to use ExtASP.Net in our web application. It is a closed source, proprietary system which is
never distributed in source or binary form. Our customers simply access the software as a service.

My questions are:

1) Can I use ExtAsp with its GPL license in a commerical non-distributed application?

2) If not, do I have to purchase a license from ExtJs because ExtAsp uses it?